code: def version(self) -> str:
      return str(self.effective_start_date)
  
file_path: hail/batch/batch/driver/pricing.py
imports: import abc
  from typing import Optional
  from hailtop.utils import time_msecs
label_desc: Use image node_id 3 for calling the Price obj's underlying member method code with example usage: obj.version() and returns: str